source: branches/3.2/mindi-busybox/procps/sysctl.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
File size: 7.0 KB
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[821]1/* vi: set sw=4 ts=4: */
2/*
3 * Sysctl 1.01 - A utility to read and manipulate the sysctl parameters
4 *
5 * Copyright 1999 George Staikos
6 *
[2725]7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
[821]8 *
9 * Changelog:
[2725]10 * v1.01   - added -p <preload> to preload values from a file
11 * v1.01.1 - busybox applet aware by <solar@gentoo.org>
[821]12 */
13
[3232]14//usage:#define sysctl_trivial_usage
15//usage:       "[OPTIONS] [KEY[=VALUE]]..."
16//usage:#define sysctl_full_usage "\n\n"
17//usage:       "Show/set kernel parameters\n"
18//usage:     "\n    -e  Don't warn about unknown keys"
19//usage:     "\n    -n  Don't show key names"
20//usage:     "\n    -a  Show all values"
21/* Same as -a, no need to show it */
22/* //usage:     "\n -A  Show all values in table form" */
23//usage:     "\n    -w  Set values"
24//usage:     "\n    -p FILE Set values from FILE (default /etc/sysctl.conf)"
25//usage:     "\n    -q      Set values silently"
26//usage:
27//usage:#define sysctl_example_usage
28//usage:       "sysctl [-n] [-e] variable...\n"
29//usage:       "sysctl [-n] [-e] [-q] -w variable=value...\n"
30//usage:       "sysctl [-n] [-e] -a\n"
31//usage:       "sysctl [-n] [-e] [-q] -p file   (default /etc/sysctl.conf)\n"
32//usage:       "sysctl [-n] [-e] -A\n"
33
[1765]34#include "libbb.h"
[821]35
[2725]36enum {
37    FLAG_SHOW_KEYS       = 1 << 0,
38    FLAG_SHOW_KEY_ERRORS = 1 << 1,
39    FLAG_TABLE_FORMAT    = 1 << 2, /* not implemented */
40    FLAG_SHOW_ALL        = 1 << 3,
41    FLAG_PRELOAD_FILE    = 1 << 4,
[3232]42/* TODO: procps 3.2.8 seems to not require -w for KEY=VAL to work: */
[2725]43    FLAG_WRITE           = 1 << 5,
[3232]44    FLAG_QUIET           = 1 << 6,
[2725]45};
[3232]46#define OPTION_STR "neAapwq"
[821]47
[2725]48static void sysctl_dots_to_slashes(char *name)
[821]49{
[2725]50    char *cptr, *last_good, *end;
[821]51
[2725]52    /* Convert minimum number of '.' to '/' so that
53     * we end up with existing file's name.
54     *
55     * Example from bug 3894:
56     * net.ipv4.conf.eth0.100.mc_forwarding ->
57     * net/ipv4/conf/eth0.100/mc_forwarding
58     * NB: net/ipv4/conf/eth0/mc_forwarding *also exists*,
59     * therefore we must start from the end, and if
60     * we replaced even one . -> /, start over again,
61     * but never replace dots before the position
62     * where last replacement occurred.
63     *
64     * Another bug we later had is that
65     * net.ipv4.conf.eth0.100
66     * (without .mc_forwarding) was mishandled.
67     *
68     * To set up testing: modprobe 8021q; vconfig add eth0 100
69     */
70    end = name + strlen(name);
71    last_good = name - 1;
72    *end = '.'; /* trick the loop into trying full name too */
[821]73
[2725]74 again:
75    cptr = end;
76    while (cptr > last_good) {
77        if (*cptr == '.') {
78            *cptr = '\0';
79            //bb_error_msg("trying:'%s'", name);
80            if (access(name, F_OK) == 0) {
81                *cptr = '/';
82                //bb_error_msg("replaced:'%s'", name);
83                last_good = cptr;
84                goto again;
[821]85            }
[2725]86            *cptr = '.';
[821]87        }
[2725]88        cptr--;
[821]89    }
[2725]90    *end = '\0';
91}
[821]92
[2725]93static int sysctl_act_on_setting(char *setting)
94{
95    int fd, retval = EXIT_SUCCESS;
96    char *cptr, *outname;
97    char *value = value; /* for compiler */
[821]98
[2725]99    outname = xstrdup(setting);
[821]100
[2725]101    cptr = outname;
102    while (*cptr) {
103        if (*cptr == '/')
104            *cptr = '.';
105        cptr++;
[821]106    }
107
[2725]108    if (option_mask32 & FLAG_WRITE) {
109        cptr = strchr(setting, '=');
110        if (cptr == NULL) {
111            bb_error_msg("error: '%s' must be of the form name=value",
112                outname);
113            retval = EXIT_FAILURE;
114            goto end;
[821]115        }
[2725]116        value = cptr + 1;  /* point to the value in name=value */
117        if (setting == cptr || !*value) {
118            bb_error_msg("error: malformed setting '%s'", outname);
119            retval = EXIT_FAILURE;
120            goto end;
[821]121        }
[2725]122        *cptr = '\0';
123        outname[cptr - setting] = '\0';
124        /* procps 3.2.7 actually uses these flags */
125        fd = open(setting, O_WRONLY|O_CREAT|O_TRUNC, 0666);
126    } else {
127        fd = open(setting, O_RDONLY);
[821]128    }
129
[1765]130    if (fd < 0) {
[821]131        switch (errno) {
132        case ENOENT:
[2725]133            if (option_mask32 & FLAG_SHOW_KEY_ERRORS)
134                bb_error_msg("error: '%s' is an unknown key", outname);
[821]135            break;
136        default:
[2725]137            bb_perror_msg("error %sing key '%s'",
138                    option_mask32 & FLAG_WRITE ?
139                        "sett" : "read",
140                    outname);
[821]141            break;
142        }
[2725]143        retval = EXIT_FAILURE;
144        goto end;
145    }
146
147    if (option_mask32 & FLAG_WRITE) {
148//TODO: procps 3.2.7 writes "value\n", note trailing "\n"
149        xwrite_str(fd, value);
150        close(fd);
[3232]151        if (!(option_mask32 & FLAG_QUIET)) {
152            if (option_mask32 & FLAG_SHOW_KEYS)
153                printf("%s = ", outname);
154            puts(value);
155        }
[821]156    } else {
[2725]157        char c;
158
159        value = cptr = xmalloc_read(fd, NULL);
[821]160        close(fd);
[2725]161        if (value == NULL) {
162            bb_perror_msg("error reading key '%s'", outname);
163            goto end;
[821]164        }
[2725]165
166        /* dev.cdrom.info and sunrpc.transports, for example,
167         * are multi-line. Try "sysctl sunrpc.transports"
168         */
169        while ((c = *cptr) != '\0') {
170            if (option_mask32 & FLAG_SHOW_KEYS)
171                printf("%s = ", outname);
172            while (1) {
173                fputc(c, stdout);
174                cptr++;
175                if (c == '\n')
176                    break;
177                c = *cptr;
178                if (c == '\0')
179                    break;
180            }
181        }
182        free(value);
[821]183    }
[2725]184 end:
[821]185    free(outname);
186    return retval;
[2725]187}
[821]188
[2725]189static int sysctl_act_recursive(const char *path)
[821]190{
[2725]191    DIR *dirp;
192    struct stat buf;
193    struct dirent *entry;
194    char *next;
[821]195    int retval = 0;
196
[2725]197    stat(path, &buf);
198    if (S_ISDIR(buf.st_mode) && !(option_mask32 & FLAG_WRITE)) {
199        dirp = opendir(path);
200        if (dirp == NULL)
201            return -1;
202        while ((entry = readdir(dirp)) != NULL) {
203            next = concat_subpath_file(path, entry->d_name);
204            if (next == NULL)
205                continue; /* d_name is "." or ".." */
206            /* if path was ".", drop "./" prefix: */
207            retval |= sysctl_act_recursive((next[0] == '.' && next[1] == '/') ?
[3232]208                    next + 2 : next);
[2725]209            free(next);
[821]210        }
[2725]211        closedir(dirp);
[821]212    } else {
[2725]213        char *name = xstrdup(path);
214        retval |= sysctl_act_on_setting(name);
215        free(name);
[821]216    }
217
218    return retval;
[2725]219}
[821]220
[2725]221/* Set sysctl's from a conf file. Format example:
222 * # Controls IP packet forwarding
223 * net.ipv4.ip_forward = 0
224 */
225static int sysctl_handle_preload_file(const char *filename)
226{
227    char *token[2];
228    parser_t *parser;
[821]229
[2725]230    parser = config_open(filename);
231    /* Must do it _after_ config_open(): */
232    xchdir("/proc/sys");
[3232]233    /* xchroot("/proc/sys") - if you are paranoid */
[821]234
[2725]235//TODO: ';' is comment char too
236//TODO: comment may be only at line start. "var=1 #abc" - "1 #abc" is the value
237// (but _whitespace_ from ends should be trimmed first (and we do it right))
238//TODO: "var==1" is mishandled (must use "=1" as a value, but uses "1")
239// can it be fixed by removing PARSE_COLLAPSE bit?
240    while (config_read(parser, token, 2, 2, "# \t=", PARSE_NORMAL)) {
241        char *tp;
242        sysctl_dots_to_slashes(token[0]);
243        tp = xasprintf("%s=%s", token[0], token[1]);
244        sysctl_act_recursive(tp);
245        free(tp);
246    }
247    if (ENABLE_FEATURE_CLEAN_UP)
248        config_close(parser);
249    return 0;
250}
251
252int sysctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
253int sysctl_main(int argc UNUSED_PARAM, char **argv)
[821]254{
[2725]255    int retval;
256    int opt;
[821]257
[2725]258    opt = getopt32(argv, "+" OPTION_STR); /* '+' - stop on first non-option */
259    argv += optind;
260    opt ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS);
261    option_mask32 = opt;
[821]262
[2725]263    if (opt & FLAG_PRELOAD_FILE) {
264        option_mask32 |= FLAG_WRITE;
265        /* xchdir("/proc/sys") is inside */
266        return sysctl_handle_preload_file(*argv ? *argv : "/etc/sysctl.conf");
[821]267    }
[2725]268    xchdir("/proc/sys");
[3232]269    /* xchroot("/proc/sys") - if you are paranoid */
[2725]270    if (opt & (FLAG_TABLE_FORMAT | FLAG_SHOW_ALL)) {
271        return sysctl_act_recursive(".");
272    }
[821]273
[2725]274    retval = 0;
275    while (*argv) {
276        sysctl_dots_to_slashes(*argv);
277        retval |= sysctl_act_recursive(*argv);
278        argv++;
279    }
280
[821]281    return retval;
[2725]282}
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